CVE-2023-35921
📋 TL;DR
This vulnerability affects multiple SIMATIC MV500 series industrial cameras. An unauthenticated remote attacker can send specially crafted Ethernet frames to cause a denial of service, requiring manual device restart. All versions before V3.3.4 are vulnerable.
💻 Affected Systems
- SIMATIC MV540 H
- SIMATIC MV540 S
- SIMATIC MV550 H
- SIMATIC MV550 S
- SIMATIC MV560 U
- SIMATIC MV560 X
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Persistent denial of service attacks could render critical industrial cameras unavailable, disrupting production processes that rely on visual inspection or monitoring.
Likely Case
Temporary camera unavailability requiring manual intervention to restart affected devices, causing operational disruption.
If Mitigated
With proper network segmentation and access controls, impact is limited to isolated camera networks with minimal production disruption.
🎯 Exploit Status
Exploitation requires sending specially crafted Ethernet frames to the device, which is relatively straightforward for attackers with network access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: V3.3.4
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-561322.pdf
Restart Required: Yes
Instructions:
1. Download firmware V3.3.4 from Siemens support portal. 2. Backup current configuration. 3. Upload and install new firmware via web interface or TIA Portal. 4. Restart device. 5. Verify firmware version.
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected cameras in separate VLANs with strict firewall rules to limit exposure.
Access Control Lists
allImplement network ACLs to restrict which devices can communicate with the cameras.
🧯 If You Can't Patch
- Implement strict network segmentation to isolate cameras from untrusted networks
- Deploy network monitoring to detect and block malicious Ethernet frame patterns
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface (System > Information) or TIA Portal. If version is below V3.3.4, device is vulnerable.Check Version:
No CLI command - check via web interface at http://<device-ip>/system/info or via TIA PortalVerify Fix Applied:
Confirm firmware version shows V3.3.4 or higher in device web interface or TIA Portal.📡 Detection & Monitoring
Log Indicators:
- Device restart logs without user intervention
- Network interface errors or resets
Network Indicators:
- Unusual Ethernet frame patterns to camera ports
- Sudden loss of camera connectivity
SIEM Query:
source="network_firewall" AND (dest_port=80 OR dest_port=443) AND dest_ip="camera_subnet" AND protocol="TCP" AND bytes>unusual_threshold